NetExtensionGetFragmentMdl function (mdl.h)

Article
02/22/2024

The NetExtensionGetFragmentMdl function retrieves the DMA MDL extension information for a net fragment.

Syntax

EXTERN_C_START NET_FRAGMENT_MDL * NetExtensionGetFragmentMdl(
  NET_EXTENSION const *Extension,
  UINT32              Index
);

Parameters

Extension

A pointer to a NET_EXTENSION structure that describes the DMA MDL extension information for this fragment.

Index

The index in the fragment ring for the target NET_FRAGMENT.

Return value

Returns a pointer to a NET_FRAGMENT_MDL structure that contains the DMA MDL information for the fragment.

Remarks

NIC client drivers typically query offsets for fragment extensions during datapath queue creation, then store them in their queue context space so they don't have to query them too often. For an example of this, see Transmit and receive queues. Clients can retrieve the DMA MDL offset from the queue context to pass to NetExtensionGetFragmentMdl.

This function is a wrapper function around NetExtensionGetData.

Requirements

Requirement	Value
Target Platform	Universal
Header	mdl.h
IRQL	Any level as long as target memory is resident